Solar-driven catalytic transformation of sugars and their derivatives

Lignocellulosic biomass can replace a portion of the petroleum and fossil fuel feedstocks, such as the carbon-based feedstock fraction employed in the production of transportation biofuels (e.g., bioethanol) and platform chemicals (e.g., HMF, furfural), contributing to the production of valuable chemicals and fuels. Differentiating from traditional thermochemical and biochemical processes, photocatalysis is emerging as a more straightforward and environmentally friendly pathway for biomass conversion. This approach drives biomass transformations using photo-excited charge carriers and photo-generated reactive species, generating a different reaction pattern. Under mild conditions, photocatalysis allows the selective functionalization of targeted functional groups and the exact cleavage of particular chemical bonds. This review provides an overview of photo reactions involving the conversion of glucose or fructose to HMF, and subsequent transformation of HMF into value-added chemicals under visible or UV light irradiation, clarifying the underlying mechanisms. Potential strategies for the photocatalytic conversion of sugars are also discussed, with key challenges that should be addressed to enhance economic viability and long-term sustainability.